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' H. S. MAXIM.

ELECTRIC LAMP.

I Patented Jam. 17,1882.

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UNtTe STATES PATENT Ormes@ HIRAM S. MAXIM, OF BROOKLYN, ASSIGNOR TO THE UNITED STATES ELEO- i TRIO LIGHTING COMPANY, OF NE W YORK, N. Y. f

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 252,392, dated January 17', 1882.

` Application tiled March 25, 1881. (No model.)

To all whom it may concern:

Be it known that I, Hman S. MAXIM, re-

siding at Brooklyn, in the county ofKings and State of New York, have invented certain new and useful Improvements in Electric Lamps,

of which the following is a specification.

The object of my invention is to lessen the cost, without imp airing the efficiency, of incandescent lamps, and this I eEect by the 1o methods employed in theirmanufacture, which I have hereinafter more fully set forth and claimed.

The two most important steps in the production ofthelampsabove mentioned are the manufacture of the carbon-conductors and the sealing of the metallic wires supporting the same into the glass. These two steps have heretofore beenaccomplished in substantially the following manner:

2o A loop or strip of the desired material is irst cut out, and this is carbonized either in its original shape or while bent to the'form of a loop, with the object of obtaining as large a radiating surface as possible within small compass. This entails considerable difficulty and expense, as the loops are liable to warp and break. v

Secondly, the metal conductors are sealed into the glass either directly or by the inter position ofametallo-vitreous cement, such us that described in Patent No.236,833; butthis necessarily involves the delicate operation of glass-blowing, and requires the highest order of skilled workmanship for its successful attaiument.

` With a view to avoid these diflcultesin the manufacture of incandescent lamps I have devised the following methods ot' producing` a complete lamp at a greatly reduced cost.

To for'm the conductor, I first cut out'separate straight strips of paper orother material with broadened ends and of aboutone-half the usual length. 'These I carhonize in the usual l manner, and join two of them in the form ofa V to opposite sides of a small block of metal or carbon by nuts'and screws, or by any of the known forms ot' clamps used for such purposes. The free ends may then be united to the metal supporting conductors of any incandescent lamp, and the conducting medium thus formed 5o Then, by a drill applied in the indentatiotis, I 6o I form comparativelyl small perforations completely through the glass. Through the holes thus obtained the small ends 'of slightly-tapering copper wires are drawn, and the spaces around the wires lled with powdered gumcopal. The whole is then subjected to a high temperature, and the wires-drawn through until they completely and tightly till the perforations. In being drawn through the glass, as through a die, the wires carry along with them 7o a small quantity of the copal, which forms, when cold, an absolutely tight joint. The. stopper, when completed by the addition of a` carbon-conductor, which is united to the ends ofthe wires, may he fitted into the open end of an ordinary lamp-globe by a ground-glassjoin t,

which, for additional security, may have a thin Iilm of cement or gum between its faces.

The drawings hereto annexed illustrate the lamp complete and its several component parts. 8o

Figure l is a view of the lamp entire. Fig.

2 is a plan and section view of the glass stopper; and Fig. 3 represents one of the carbon conductors.

A is the lamp globe, with a neck, into which is fitted by a ground joint, either-with or without cement, the stopper B.

O O are theindentations, as described, formed in the process of molding, and which serve as receptacles for cement or gum when it is de- 9o sired to employ the sameas an additional security against the access of air into the globe.

DD are the coppercond uctors drawn through vthe stopper, and to which are attached the free ends of the conductors E E, the other ends of which are united, as shown, by clamps or otherwise, to F, which is a small mass of metal or carbon of such degree of conductivity as not to become heated to incandescence by the passage of the current.

It may be observed that the strips F, instead of being made as described, may be composed of any of the carbonaceous compounds used in incandescent lighting.

Alamp thus made is both durable and cheap, and may be constructed by any ordinarilyskilled workman. The exhaustion of the confined air is effected as in other forms, and much that involves the art of glass-blowing lis dispensed with in its manufacture.

I am aware that a straight carbon in an incandescent lamp is not broadly new; nor do I claim, broadly, herein a ground-glass stopper containing the conducting-wires; but

What I do claim as myinvention, and desire to secure by Letters Patent, is-

41. A carbon conductor for electric incandescent lamps composed of independent straight strips or filaments of carbon, the ends of which are connected respectively to a small mass oi' conductingmaterial and to the supporting-conductors, as set forth.

2. The combination, with the globe of an incandescent electric lamp, of an air-tight stopper of glass having partly conical perfcrations and conducting-wires of ductilc metal contained therein, as set forth.

3. The method herein described of sealing the metallic conductors of an incandescent lamp, which consists in drawing under a high temperature the tapering ends ot' the same through perforations in a glass stopper, either with or without'the addition of a fusible gum, as set forth.

4. The ground-glass stopper B, having metallic wires D D embedded therein, and the conical indentations C C, for retaining a suitable eement or gum.

In testimony whereof I have hereunto set my hand this 23d day of March, 1881, and in the presence ot' two subscribing witnesses.

HIRA M S. MAXIM.

Witnesses:

JAS. C. RoBlNsoN, A. M. AKE. 

